Cisco GainMaker Optoelectronic Node 1GHz with 65 86 MHz Split Installation Guide
Balancing the Reverse Path
MHz range.
The amplitude of the signal generator output can be set higher or lower than the
level specified by the calculation above, but the difference between the actual
output level and the level calculated above must be known. If the generator
output is x dB higher (or lower) than the level calculated, then the reference
(desired) level received at the headend or hub should also be x dB higher (or
lower) than the original headend reference level.
The station reverse input pad values are selected during the reverse system
design and are based on the need to minimize variations in return path losses for
the various reverse inputs. Do not permanently alter the values of the reverse
input pads without consulting a system designer.
In the GainMaker node, the reverse input comes after the reverse injection point
in the reverse path. Temporarily replacing the design value reverse input pad on
the port being balanced with a 0 dB pad allows the reverse injection level and the
receive levels at the monitoring end to remain constant from amplifier to
amplifier and from port to port.
An alternative to this method is to expect a receive level that is x dB lower than
An alternative to this method is to expect a receive level that is x dB lower than
normal, where x is the value of the reverse input pad on the port being balanced,
which you noted earlier in the reverse path balancing procedure.
High Gain Dual Pad Values
While most system design prints should specify a design value reverse input pad for
While most system design prints should specify a design value reverse input pad for
each port, the following chart provides guidelines for minimum reverse input pad
values that should be installed for the High Gain Dual with an Auxiliary Signal
Director (other than a jumper) installed in the amplifier module.
Signal Director
Tap Leg
Thru Leg
Splitter
3.5 dB
3.5 dB
DC-8
8.0 dB
2.0 dB
DC-12
12.0 dB
1.5 dB
Unlike previous versions of the High Gain Dual with plug-in signal directors, the
GainMaker amplifier signal director creates loss in the forward path only. To
equalize forward and reverse path losses, these minimum pad values are
recommended on the associated reverse input ports.
Note: Design print values may be greater than the minimum recommended reverse
Note: Design print values may be greater than the minimum recommended reverse
input port pad values listed above.
Insert the appropriate signal amplitude into the reverse injection point. Refer to the
Insert the appropriate signal amplitude into the reverse injection point. Refer to the
following illustration.
OL-30326-02
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